There are a lot of coatings out there that claim this tough metal or this 1 million rockwell hardness. Will any of them really extend the life of a bolt, or prevent bolt breakage? Stuff like Hard Chrome, NP3, Ionbond, Nickel Boron, 9310 steel, etc.?
I havn’t seen any of them claiming longer bolt life, just more reliability with less lubrication/cleaning.
9310 steel is a material for an entire bolt or carrier. I’ve read and I can’t determine whether it’s better, worse, or basically the same as Carpenter 158, the milspec alloy for bolts. Maybe an engineer or metallurgist can comment on that.
The other items you list - “Hard Chrome, NP3, Ionbond, Nickel Boron” - are all just coatings and I haven’t seen any claims of longer life. All the claims seem to be that they eliminate any need for lubrication and therefore provide greater reliability. All of those are also fairly hard, but a common carrier is made of 8620 steel which can be case hardened to the upper 50’s on the Rockwell scale, which is plenty hard.
I e-mailed Carpenter about this. The mettalurgist that replied said C158 is stronger than 9310. The reason smaller shops use 9310 instead is because they can buy it in smaller lots. To purchase C158 means you have to buy a minimum lot of something like 20 tons.
I think this is correct. A company has to purchase an entire heat treat lot of C158 from Carpenter. One complete lot costs over 100K.
:blink:
This is 100% correct, a side from combining orders with your competition or being a large manufacture yourself it is very tough to use 158 for production.
If you dont mind paying a little extra a chrome plated BCG and bolt are worth it, besides being a bit tougher they provide natural lubricating properties which make cleaning and functioning much easier.
I prefer a more porous surface treatment so that the lube sticks to it, and does its job.
The coatings you mention will make cleaning easier, which in itself, will extend your rifles life and yours (less time cleaning!). Seriously, I have about 9 BCG’s I’d like done in boron nickle, so maybe a group order is in order!
I can understand this line of thinking, but IME grease sticks just fine to Nickel Boron. If you stay away from the thinner stuff.
If you tried a smoother surface, with more grease, you’d probably be pleased.
Something to mabe consider when choosing between a coating like chrome and a surface treatment like parkerizing:
Being a coating, it goes over top of the item being coated with very little if any impregnation and is slightly flexible as a result, (think flaked chrome on a bumper), so its entirely possible that small stress fractures in the item itself can remain invisible up to the point of catastrophic failure rather than being spotted much earlier and the item replaced if a surface treatment were used instead.
There’s also the issue of coatings primarily starting to fail at about any sharp corner they come to. A very poor anology would be like trying to wrap foil onto something with a complex shape. Yeah, you can cover it, but the corners will always not be covered quite as well, and if you bump it, it’s always a corner or edge that tears first.
(how many corners and edges are on a bolt, and what part of the bolt gets the most beating during cycling?)
With all that in mind, did a coating start to fail because of fair wear and tear, and how much more wear and tear will the edges of the failed coating create on other parts they come in contact with?
Or, is the failure a result of some underlying damage that you can’t see/inspect because the coating is covering it up from view?
Yes, extenuating circumstances, but entirely plausible if everything wasn’t done perfectly, and even then still possible due to external variables.
What about during cold weather?
Personally, I don’t see the point to so-called “improved” coatings. The current set up acts in a predictable manner under all the conditions I normally encounter without mind-fucking it, which is all I need.
I don’t get the “less time cleaning” thing.
The system works just fine dirty, and should I want it “clean” I either swipe it with a cloth, or shoot it with an aerosol cleaner.
I may have my issues, but this pathological desire to clean ARs is not one of them.
Truly, mind-fucking this issue would be to ignore the advanced coatings that have been invented in the ~45 years since the AR15’s inception.
It’s this simple: reducing friction is simply good engineering and is a plus in all but a small fraction of engineering applications. Less friction means longer part life. Several new coatings reduce friction in the AR platform and, so far, are doing it FAR better than phosphating.
And yes, the current phosphate coating on my old CMT BCG predictably FAILED to operate reliably absent lube after about 500 rds. My NiB Fail Zero BCG doesn’t have this issue.
My NiB BCG runs perfectly in 20 degree weather using tula 55gr ammo and Slip 2k EWG grease. I’ve also used (you could call it abused if you would like) an IonBond BCG and a hardchrome BCG recently. They both tolerate a lack of lube far better than any phosphated BCG I’ve used. This is an increase in reliability. THIS is an improvement in performance.
With no sarcasm, I ask you: how many of these BCGs have you tested?
I’m not going to try to convince you of anything.
They work well in cold from what I know. I’ve heard of them working well to -40 degrees or so, but can’t confirm it. Personally I think it works well.
If what you’re doing now works for you, then that’s all that matters.
Interesting point about coating advances in the last 45 years. The problem with “engineering” is that often engineers fail, or underestimate secondary, tertiary and unintended consquences of their decisions. I’m an airplane mechanic in another life, and private aircraft systems are incredibly antiquated, because frankly, the older systems work reliably, and most “advances” in engine/structure end badly for airplanes. Engineers are epically underequipped, imo, to calculate downstream problems their decisions create.
So… 500 rounds later, your CMT bolt failed to function. I’m sure that XXX miles after you fill with fuel, your tank will run out as well.
One last question. Why do I need to sample all the various coatings? When all I am arguing is that the reasons given by their advocates are irrelevant in practical terms. Of course, if they want to sell their improved bolts and bolt carrier groups for the same price as phosphated ones, and the coatings do no harm, I would gladly use one. Provided I needed a bolt and carrier group, of course, since the ones I have now work just fine.
That’s an interesting assertion.
You don’t need to do anything. But you’ve supplied zero data to support your point. These coatings reduce friction in a meaningful and quantifiable way. This friction reduction boosts the MTBF of an AR15 with little lubrication.
Enjoy your phosphating. I’ll enjoy my NiB (and maybe an IONbond in the future) BCG that is a more refined and reliable part.
If phosphating works for you…enjoy it. I’m not saying you NEED a better coating. What I am saying is that making general and ambiguous statements about nebulous engineering failures does not mean that these coatings don’t provide meaningful improvements for the AR platform. These coatings are advancing the art.
These coatings reduce friction (as claimed) and increase reliability. Please explain to me how that is irrelevant to a platform that is dependent upon proper amounts of lubrication.
These are all very true statements.
Advanced coatings offer outstanding properties and performance in other industries, some of these coatings are now used in the firearms industry with great success.
In addition to 50,000 or 100,000 live round firing cycles, Some engineering companies have set up industrial robots to simulate firing cycles. The robots can actuate millions of cycles in a week or two, allowing accelerated T&E wear studies on the various coated parts.
A Very-Advanced Industrial Diamond coating is being concept-tested on some firearm parts with good initial results. More testing time will proove or dis-prove its merits.
Some really good products are on the market now. Procure some of them and run some T&E.
The problem with engineers is that the glass is neither half full nor half empty, it was simply the wrong size to begin with.
What does that mean?
Engineers tend to design thing to be ‘just enough’ to meet whatever standards, then turn right aroudn and try to find other places that corners can be cut to help accomplish that goal.
I think its a genetic tweak they have.
Lab testing is great and can accomplish a lot, but its not going to go anywhere near the abuse that the common man can put on things through negligence, ignorance or ineptitude.
The original design Ford Pinto was a great car until engineers got to frikking around with weight and $ savings and joe everyman used them in traffic. :shrug:
Honest question regarding those million cycle simulator machines:
Do they incorporate powder contamination, heat, shock, various environments and a few other things into those cycles, or do they just run the actions back and forth X times at Y speed?
If the former, then obviously much information could be gained, if the latter, well, you can do that in your living room cycling the charging handle over and over and over while watching the new Oprah network all winter long and have about the same not~how~it’ll~actually~be~done results.
Believe me, I would love to see some new super uber treatment that would prevent the need for any lube at all and wouldn’t require more than a half a paper napkin to clean the whole mechanism to a spotless level, but I don’t see that happening anytime soon and tiny evolutionary steps just piss me off to the point of being willing to wait for a true revelation rather than some slight %~age difference.